It involves double filteration of air. Atmospheric air is drawn through prefilters and is made to pass through the work table at desired velocity of 1000 cfm ± 20.
Laminar flow is fabricated out of 18mm thick Duro Board with interior covered with epoxy paint and all exterior are covered with thick white mica sheet Environmental air is drawn by a balanced double blower through pre filters retaining more than 75% of particulates and biological contaminants larger than 0.2 to 0.3 microns. All joints are tongs and grooved type for extra sturdiness. Table top is covered with non antiglare platform of stainless steel sheet. The side panels are fixed and are made of clear 0.25 inches thick glass or perspex sheet. 
HEPA filters are fabricated out of washable synthetic non woven media. The material is moisture fungus bacteria and frost resistant and is mounted in metallic frame. The filters are DOP as per BS: 2831and are 90% efficient to 5 microns. These are made out of micro glass fibre with corrugated aluminum foil separators and mounted in anodized aluminum frame sealed with epoxy sealant and is provided with rubber gasket for proper sealing. HEPA filters are 99.97% efficient down to 0.2 to 0.3 microns and are protected by expanded metal sheet or plastic sheet and these hepa filters are provided with test reports. Hepa Filters are DOP tested from point to point with IPD less than 18mm WG and FPD less than 40mm WG at rated flow upto 90 fpm ±/-20 fpm and confirming to class 100 of revised US Federal Standard 209B. 
Blower Assembly consist of suitable American universal motor or equivalent working on 220V 50 Hz with a 15 amp. power point. Dynamically and statistically balanced blowers with air velocity 0.5 m/s make the unit least vibrant with minimum noise level i.e. less than 65db. Clean air valocity 90fpm ± 20 FPM at the outlet of Hepa filters. Provided with 1 or 2 nos. fluorescent tube lights with all necessary fittings etc. These tube lights are suitable to provide 800-1000 lux recessed in canopy and replaceable from the top of canopy. Static pressure manometer accurately calibrated to assess static pressure in HEPA Filters.
Opional Front acrylic door, Gas line fitting to connect the instrument with gas or air. UV light of 30w 254 nm.
Control panels is provided with mains indicator lamp fluorescent and UV tube switch etc.

Model                  Working                     Size of                       No. of

                                  Area                           HEPA                        HEPA
SHLF-1                  2x2x2                        2'x2'x6”                     1
SHLF-2                  3x2x2                       3'x2'x6”                      1
SHLF-3                  4x2x2                       2'x2'x6”                      2
SHLF-4                  6x2x2                       3'x2'x6”                      2

-do- same as above but with complete body made of Steel Sheet duly powder
coated. Mounted on castor wheels.

Model                  Working                     Size of                       No. of

                                  Area                           HEPA                        HEPA
HMSB-1                 2x2x2                        2'x2'x6”                     1
HMSB-2                 3x2x2                       3'x2'x6”                      1
HMSB-3                 4x2x2                       2'x2'x6”                      2
HMSB-4                 6x2x2                       3'x2'x6”                      2

OPTIONAL ACCESSORIES
Magneheilic Pressure Manometer
UV Light with fittings
Timer for U.V. Lights.
Caster Wheels.
Particle Dust Count-Validation at site.
Transparent acrylic door of 5mm thick for 2'x2'x2' OR 3'x2'x2’ / 4'x2'x2' OR 6'x2'x2’